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https://github.com/roc-lang/roc.git
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Remove "Roc host" specifics from Wasm dead code elimination
This commit is contained in:
Brian Carroll
parent
18195c8bd7
commit
e57ca0aa12
3 changed files with 39 additions and 34 deletions
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@ -56,7 +56,8 @@ pub struct WasmBackend<'a> {
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module: WasmModule<'a>,
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layout_ids: LayoutIds<'a>,
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pub fn_index_offset: u32,
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called_preload_fns: BitVec<usize>,
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import_fn_count: u32,
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called_fns: BitVec<usize>,
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pub proc_lookup: Vec<'a, ProcLookupData<'a>>,
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host_lookup: Vec<'a, (&'a str, u32)>,
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helper_proc_gen: CodeGenHelp<'a>,
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@ -104,9 +105,12 @@ impl<'a> WasmBackend<'a> {
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}
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module.link_host_to_app_calls(env.arena, host_to_app_map);
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let host_function_count = module.import.imports.len()
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+ (module.code.dead_import_dummy_count + module.code.function_count) as usize;
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let import_fn_count = module.import.function_count();
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let host_function_count = import_fn_count
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+ module.code.dead_import_dummy_count as usize
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+ module.code.function_count as usize;
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let mut called_fns = BitVec::repeat(false, host_function_count);
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called_fns.extend(std::iter::repeat(true).take(proc_lookup.len()));
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WasmBackend {
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env,
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@ -114,10 +118,10 @@ impl<'a> WasmBackend<'a> {
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// Module-level data
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module,
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layout_ids,
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fn_index_offset,
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called_preload_fns: BitVec::repeat(false, host_function_count),
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import_fn_count: import_fn_count as u32,
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called_fns,
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proc_lookup,
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host_lookup,
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helper_proc_gen,
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@ -261,6 +265,8 @@ impl<'a> WasmBackend<'a> {
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source,
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});
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self.called_fns.push(true);
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let linker_symbol = SymInfo::Function(WasmObjectSymbol::ExplicitlyNamed {
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flags: 0,
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index: wasm_fn_index,
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@ -278,7 +284,7 @@ impl<'a> WasmBackend<'a> {
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self.maybe_call_host_main();
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let fn_table_size = 1 + self.module.element.max_table_index();
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self.module.table.function_table.limits = Limits::MinMax(fn_table_size, fn_table_size);
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(self.module, self.called_preload_fns)
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(self.module, self.called_fns)
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}
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/// If the host has a `main` function then we need to insert a `_start` to call it.
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@ -329,7 +335,7 @@ impl<'a> WasmBackend<'a> {
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self.code_builder.build_fn_header_and_footer(&[], 0, None);
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self.reset();
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self.called_preload_fns.set(main_fn_index as usize, true);
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self.called_fns.set(main_fn_index as usize, true);
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}
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/// Register the debug names of Symbols in a global lookup table
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@ -1337,10 +1343,9 @@ impl<'a> WasmBackend<'a> {
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.find(|(fn_name, _)| *fn_name == name)
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.unwrap_or_else(|| panic!("The Roc app tries to call `{}` but I can't find it!", name));
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self.called_preload_fns.set(*fn_index as usize, true);
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self.called_fns.set(*fn_index as usize, true);
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let host_import_count = self.fn_index_offset - self.module.code.function_count;
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if *fn_index < host_import_count {
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if *fn_index < self.import_fn_count {
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self.code_builder
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.call_import(*fn_index, num_wasm_args, has_return_val);
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} else {
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@ -177,17 +177,17 @@ impl<'a> WasmModule<'a> {
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})
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}
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pub fn eliminate_dead_code(&mut self, arena: &'a Bump, called_host_fns: BitVec<usize>) {
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pub fn eliminate_dead_code(&mut self, arena: &'a Bump, called_fns: BitVec<usize>) {
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if DEBUG_SETTINGS.skip_dead_code_elim {
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return;
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}
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//
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// Mark all live host functions
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// Mark all live functions
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//
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let import_count = self.import.imports.len();
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let host_fn_min = import_count as u32 + self.code.dead_import_dummy_count;
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let host_fn_max = host_fn_min + self.code.function_count;
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let fn_index_min = import_count as u32 + self.code.dead_import_dummy_count;
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let fn_index_max = called_fns.len() as u32;
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// All functions exported to JS must be kept alive
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let exported_fns = self
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@ -213,13 +213,13 @@ impl<'a> WasmModule<'a> {
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);
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// Trace callees of the live functions, and mark those as live too
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let live_flags = self.trace_live_host_functions(
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let live_flags = self.trace_live_functions(
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arena,
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called_host_fns,
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called_fns,
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exported_fns,
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indirect_callees_and_signatures,
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host_fn_min,
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host_fn_max,
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fn_index_min,
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fn_index_max,
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);
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//
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@ -267,9 +267,9 @@ impl<'a> WasmModule<'a> {
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self.names.function_names[old_index].1 = new_name;
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}
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// Relocate calls from host to JS imports
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// Relocate calls from to JS imports
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// This must happen *before* we run dead code elimination on the code section,
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// so that byte offsets in the host's linking data will still be valid.
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// so that byte offsets in the linking data will still be valid.
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for (new_index, &old_index) in live_import_fns.iter().enumerate() {
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if new_index == old_index {
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continue;
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@ -288,7 +288,7 @@ impl<'a> WasmModule<'a> {
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//
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let mut buffer = Vec::with_capacity_in(self.code.bytes.len(), arena);
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self.code.function_count.serialize(&mut buffer);
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for (i, fn_index) in (host_fn_min..host_fn_max).enumerate() {
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for (i, fn_index) in (fn_index_min..fn_index_max).enumerate() {
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if live_flags[fn_index as usize] {
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let code_start = self.code.function_offsets[i] as usize;
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let code_end = self.code.function_offsets[i + 1] as usize;
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@ -301,14 +301,14 @@ impl<'a> WasmModule<'a> {
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self.code.bytes = buffer;
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}
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fn trace_live_host_functions<I: Iterator<Item = u32>>(
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fn trace_live_functions<I: Iterator<Item = u32>>(
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&self,
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arena: &'a Bump,
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called_host_fns: BitVec<usize>,
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called_fns: BitVec<usize>,
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exported_fns: I,
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indirect_callees_and_signatures: Vec<'a, (u32, u32)>,
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host_fn_min: u32,
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host_fn_max: u32,
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fn_index_min: u32,
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fn_index_max: u32,
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) -> BitVec<usize> {
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let reloc_len = self.reloc_code.entries.len();
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@ -345,10 +345,10 @@ impl<'a> WasmModule<'a> {
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);
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// Loop variables for the main loop below
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let mut live_flags = BitVec::repeat(false, called_host_fns.len());
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let mut next_pass_fns = BitVec::repeat(false, called_host_fns.len());
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let mut current_pass_fns = called_host_fns;
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for index in exported_fns.filter(|i| *i < host_fn_max) {
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let mut live_flags = BitVec::repeat(false, called_fns.len());
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let mut next_pass_fns = BitVec::repeat(false, called_fns.len());
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let mut current_pass_fns = called_fns;
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for index in exported_fns.filter(|i| *i < fn_index_max) {
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current_pass_fns.set(index as usize, true);
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}
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@ -360,12 +360,12 @@ impl<'a> WasmModule<'a> {
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// For each live function in the current pass
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for fn_index in current_pass_fns.iter_ones() {
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// Skip JS imports and Roc functions
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if fn_index < host_fn_min as usize || fn_index >= host_fn_max as usize {
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if fn_index < fn_index_min as usize || fn_index >= fn_index_max as usize {
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continue;
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}
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// Find where the function body is
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let offset_index = fn_index - host_fn_min as usize;
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let offset_index = fn_index - fn_index_min as usize;
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let code_start = self.code.function_offsets[offset_index];
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let code_end = self.code.function_offsets[offset_index + 1];
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@ -527,8 +527,8 @@ impl<'a> Serialize for FunctionSection<'a> {
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*
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* Table section
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*
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* Defines tables used for indirect references to host memory.
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* The table *contents* are elsewhere, in the ElementSection.
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* Defines tables used for indirect references to external code or data.
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* The table *contents* are in the ElementSection.
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*
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*******************************************************************/
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